test-data-factory

Test Data Factory Generation Command

You are tasked with generating comprehensive test data factories that create realistic, consistent test data for your tests. These factories should make it easy to generate valid test instances with sensible defaults while allowing customization.

Step 1: Identify Target Entities

If the user provided entity/model names:

• Locate the corresponding data models, classes, or type definitions
• Identify all properties and their types
• Understand relationships between entities

If no specific entities are provided:

• Scan the codebase for data models
• Suggest common entities: User, Product, Order, etc.
• Show recently modified models

Common entity locations:

• TypeScript: interfaces, types, models
• Python: models.py, schemas.py, dataclasses
• Java: entity classes, DTOs
• Go: structs

Step 2: Analyze Entity Structure

For each entity, extract:

Basic Properties

• Property names
• Data types (string, number, boolean, date, etc.)
• Required vs optional fields
• Default values
• Constraints (min/max, length, format)

Complex Properties

• Nested objects
• Arrays and collections
• Enums and unions
• Relationships (foreign keys, references)

Validation Rules

• Format requirements (email, URL, phone)
• Range constraints (min, max values)
• Length limits
• Regular expression patterns
• Custom validators

Example Analysis:

// Source: User.ts
interface User {
  id: string;              // UUID
  email: string;           // Valid email format
  firstName: string;       // 1-50 chars
  lastName: string;        // 1-50 chars
  age?: number;           // Optional, 18-120
  role: 'admin' | 'user'; // Enum
  createdAt: Date;
  settings: UserSettings; // Nested object
  orders: Order[];        // Array of related entities
}

Step 3: Detect Faker/Mock Library

Identify available data generation libraries:

JavaScript/TypeScript

• @faker-js/faker (recommended): Comprehensive fake data
• chance: Random data generator
• casual: Fake data for testing
• Install if not present: npm install -D @faker-js/faker